List the elements Na,Ca,Rb,Cl,He in order of decreasing first ionization energy.
A)He Cl Ca Na Rb
B)He Na Ca Cl Rb
C)He Na Cl Ca Rb
D)Rb Ca Cl Na He

Question

List the elements Na,Ca,Rb,Cl,He in order of decreasing first ionization energy.
A)He > Cl > Ca > Na > Rb
B)He > Na > Ca > Cl > Rb
C)He > Na > Cl > Ca > Rb
D)Rb > Ca > Cl > Na > He

Quizplus · Accepted Answer

First ionization energy generally increases across a period (from left to right) and decreases down a group (from top to bottom) in the periodic table. Helium (He), being a noble gas, has the highest first ionization energy. Among the remaining elements, chlorine (Cl) is next due to its high electronegativity and smaller size compared to the metals. Among the metals, the ionization energy decreases from calcium (Ca) to sodium (Na) to rubidium (Rb) as we move down the group.

List the Elements Na,Ca,Rb,Cl,He in Order of Decreasing First Ionization